Question

Formation of a solution from two components can be considered as

(i) Pure solvent → separated solvent molecules, ΔH₁

(ii) Pure solute → separated solute molecules, ΔH₂

(iii) Separated solvent and solute molecules → solution, ΔH₃

Solution so formed will be ideal if

(a) ΔH_soln = ΔH₁ + ΔH₂ + ΔH₃

(b) ΔH_soln = ΔH₁ + ΔH₂ - ΔH₃

(c) ΔH_soln = ΔH₁ - ΔH₂ - ΔH_{​​​​​​​3}

(d) ΔH_soln = ΔH₃ - ΔH₁ - ΔH_{​​​​​​​2}

Answer 1

The correct option is: (a) ΔH_soln = ΔH₁ + ΔH₂ + ΔH₃

Explanation:

Heat of solution is defined as the amount of heat evolved or absorbed when one mole of the substance is dissolved in excess of the solvent. For hydrated salt and for salts which do not form hydrates. ΔH is positive and for anhydrous salts, it is negative.